General
A number of disciplines have been developed over the years in the vapor deposition art for applying or depositing a coating layer on a substrate surface within a vapor deposition chamber. Certain fundamental process steps are the same for all of the vapor deposition disciplines, although a large number of variations and techniques in implementing the process steps have been developed. Generally, the substrate to be coated is placed within a deposition chamber, which is typically evacuated or pressurized to a desired pressure. The coating material to be deposited on the substrate is generated within or introduced into the chamber, and assumes the form of a plasma that includes gaseous vapors and solid particulate matter. The plasma may include atoms, molecules, ions, and agglomerates of molecules of the coating material, as well as those of any desired reactant agents and any undesired impurities. The coating or deposition process itself occurs by condensation of the plasma coating particles onto the substrate surface(s) to be coated.
Vapor deposition coating processes are generally categorized into "chemical" and "physical" vapor deposition disciplines. Both generally incorporate a deposition or coating chamber in which a "plasma" of the coating material is produced and projected toward a substrate to be coated. The uses of the coatings applied to substrates, and the shapes and materials of the substrates can vary widely, from decorative coatings on ceramic or pottery materials, to circuit interconnection wiring paths on the surfaces of semi-conductor chips, to wear-resistant coatings on cutting tool and bearing surfaces. Similarly, the physical nature and properties of the coating materials vary widely, from conductive coatings, to semiconductive coatings, to those forming electrical insulators.